汽轮机调节阀通流及损失特性研究

Investigation on Flowrate and Total Pressure Loss of Flow Through Steam-Turbine Control Valve

依据厂方提供的设计数据,在不同升程、不同压比条件下对汽轮机调节阀三维流场特性进行了数值模拟.研究结果表明:阀碟下方的空穴区占据了阀座喉部通流面积的一部分,使得有效的通流面积减小,影响了阀门的通流能力;阀碟附近是整个流场中全压损失最大的区域,占调节阀总损失的60%以上,阀腔以及阀座扩压段内的全压损失相对较小;在相对升程小于6%、压比小于0.7后,环形通道的末端将产生激波,激波带来较大的全压损失.为了提高额定工况下调节阀的通流能力,建议其相对升程应尽可能地提高.

Three-dimensional flow characteristics of the control valve for steam turbine under the different pressure ratio and relative lift were investigated by numerical simulation with the design data provided by a manufacturer. The results show that a part of the flow passage of the valve seat is occupied by the cavity under the valve head, leading to a decrease of flow rate. The energy loss near the valve head is maximal and accounts for 60% of the total loss. At the end of the annular passage, shock wave occurs when the relative lift is less than 6% and the pressure ratio is less than 0. 7, which causes a greater total pressure loss. In order to increase the flowrate of the control valve operating under nominal working condition, the relative lift should be higher.